The invention relates to a lens array that may be used in connection with a motion sensing light fixture. More specifically the present invention generally relates to a single lens array or optical component that uses a plurality of lenses each of which has a different infrared detection pattern that may be selectively actuated to vary the infrared detection zone of the light fixture.
One particular use for the present invention is in a lighting device, whether indoor or outdoor, that has been adapted to sense xe2x80x9cmotionxe2x80x9d as a change in infrared. To do this, the lighting device typically will use a passive infrared detector (xe2x80x9cPIRxe2x80x9d) that works in combination with an optical component or lens array having a Fresnel lens which has a optical or infrared detection pattern that directs infrared to the PIR. However, because the detection pattern is generally preset or predetermined at the time of manufacture, the infrared detection pattern is accordingly preset or predetermined as well. This, in turn, limits the locations in which the lighting device may be used since the preset infrared detection pattern will only have one optimal location at which the light fixture may be mounted on a support surface that enables maximum infrared detection to occur.
To compensate for the need to varying the location of the light fixture, attempts have been made in the past to provide a degree of adjustability to the PIR to account for the fixed infrared detection pattern of the lens. In one attempt, the PIR and accompanying Fresnel lens are attached to a knuckle which allows a user to direct the lens in a plurality of directions. This solution, however, has several disadvantages including the need to manufacture and include on the fixture a bulky and adjustable housing that holds the lens and that must also extend outwardly from the fixture. This not only increases the cost of manufacture, it also impairs the aesthetic appeal of the unit, among other things.
Another method used is to make the lens and PIR a separate unit from the light fixture and to connect the components by wiring. For the reasons stated above, the solution is undesirable as well.
The present invention solves the above stated problems. It does so by providing a light fixture that includes a lens array which is in communication with a PIR. The lens array includes an optical component which has a plurality of lenses each of which has a different infrared detection pattern. The lenses of the optical component are selectively actuated thus allowing the infrared detection pattern to be adjusted to accommodate the location at which the light fixture has been placed.